There are various methods used to characterize the quality impact of reusing a frequency in a given sector or cell site with respect to all other sectors (cell sites) in a cellular or mobile communication system (“system”). Criteria available for making this judgment include C/I (Carrier/Interference) histograms, Bit Error Rate analysis, Mean Opinion Score (voice quality analysis), and engineering intuition. Oftentimes engineers use some combination of the aforementioned methods.
C/I measurements may be collected via drive testing (i.e., measuring signal strengths while actually driving around through different cell sites), propagation tools (i.e., measuring signal strength using a computer at a central location), or from a switch (i.e., using a mobile switching center (MSC) and the cell phones communicating with that MSC to determine signal strengths). Drive testing is resource-intensive and propagation tools may be prone to error, especially, for example, in heavily-populated urban areas.